Means for forming circular roofs

ABSTRACT

The ceiling for a large, buried, cylindrical, concrete tank provided with an upright, coaxial column in the center of its cavity is poured in a form including girders radiating from the column toward the outer tank wall. The inner terminal portions of the girders rest on a split collar releasably tightened on the top end of the column, and hook-like brackets on the outer terminal portions of the girders rest on the outer tank wall. The panels which downwardly close the form rest on the girders. Foam plastic pads on the outer ends of the girders facilitate removal of the girders through an access opening in the ceiling after the concrete in the ceiling has set.

United States Patent [1 1 Heinzle Dec. 17, 1974 1 MEANS FOR FORMING CIRCULAR ROOFS [76] Inventor: Otto Heinzle, Sonderberg 19,

A-6840 Gotzis, Austria [22] Filed: Dec. 26, 1972 [21] Appl. No.: 318,273

[30] Foreign Application Priority Data Dec. 24, 1971 Austria, 11120/71 [52] US. Cl. 249/19, 249/210 [51] Int. Cl. E04g 11/04 [58] Field of Search 249/1, 17-19,

[56] References Cited UNITED STATES PATENTS 106,854 8/1970 Mosley 52/263 2,932,964 4/1960 Dobell 249/1 3,161,703 12/1964 .Watson 249/19 3,436,052 4/1969 Ocampo 249/27 3,562,986 2/1971 Nelson 52/246 FOREIGN PATENTS OR APPLICATIONS 7/1909 Great Britain 249/1 682,893 3/1964 Canada 52/263 Primary ExaminerRobert D. Baldwin Assistant Examinerlohn McQuade Attorney, Agent, or Firm-Hans Berma'n [5 7 ABSTRACT The ceiling for a large, buried, cylindrical, concrete tank provided with an upright, coaxial column in the center of its cavity is poured in a form including girders radiating from the column toward the outer tank 'wall. The inner terminal portions of the girders rest on a split collar releasably tightened on the top, end of the column, and hook-like brackets 'on the outer terminal portions of the girders rest on the outer tank wall. The panels which downwardly close the form rest on the girders. Foam plastic pads on the outer ends of the girders facilitate removal. of the girdersthrough an access opening in the ceiling after the concrete in the ceiling has set.

5 Claims, 6 Drawing Figures MEANS FOR FORMING CIRCULAR ROOFS This invention relates to concrete ceilings for large tanks, and particularly to a form for pouring such ceilings. I

It is known to provide cylindrical upright tanks having a diameter of 40 feet or more with a concrete ceiling or cover which is prepared after the upright con-.

crete walls of the tank have reached substantially their full strength. A column standing near the center of the tank provides support for the finished ceiling or cover.

The outer tank wall is usually imperforate, particularly when it is intended to install'most of the tank underground, and a manhole for admitting a maintenance crew andits equipment is normally the largest opening available in the completed cover.'It has been customary to erect scaffolding in thetank to support carrier beams vation 1. The cylindrical outer concrete wall 2 of the tank is imperforate and substantially fully cured so that the form in which it was poured has been removed. The reinforcing iron in the tank is not being shown in the drawing since it is not directly relevant to this invention. The portion of the tank not visible in the drawing is substantially symmetrical to the illustrated part relative to the central, upright axis 3 of the tank. A cylindrical concrete column 4, coaxial with the outer wall 2, will support the center of a ceiling or cover that it is intended to build.

The bottom of the form for pouring the concrete ceiling is provided by wooden or steel panels not shown in detail, and conventional in themselves They are supported on fish-bellied carriers or girders 6 which radiate in approximately equiangular arrangement from the column 4 toward the wall. 2, as is partly illustrated in below the intended location of the ceiling or cover, and

and removed throughthe restricted opening in the ceil- 1 ing, an inconvenient and time-consuming task.

A primary object of the invention is the provision of a form arrangement for pouring a concrete ceiling for a tank or building of the type described which is simpier to erect and'simpler to dismantle than forms in use heretofore.

With this object and others in view, as will presently become apparent, I provide a collar which is releasably secured to the topmost portion of the available column in the tank cavity in a position in which the collar projects horizontally from the column. Horizontally elongated carrier members have each an inner, longitudinally terminal portion supported on the collar and an outer longitudinally terminal portion near the wall of the tank or building. The outer terminal portions of the carrier members are secured to the topmost portion 'of the wall in the tank cavity. Panels supported on the carriers substantially close the cavity in an upward direction and constitute the bottom of the form. An annular, upright wall of sheeting projects upwardly from the panels for horizontally containing concrete poured on the panels. 1

Other features, additional objects, and many of the attendant advantages of this invention will readily be appreciated from the following detailed description of a preferred embodiment of the invention when considered in connection with the appended drawing in which:

FIG. I shows a tank to be provided with a concrete ceiling poured in a form of the invention, the tank and form being shown in fragmentary elevational section;

FIG. 2 shows a portion of the apparatus of FIG. 1 on a larger scale;

FIG. 3 shows the device of FIG. 2 in section on the line III-III;

FIG. 4 is a top plan view of an element of the apparatus of FIG. 1; i

' FIG. 5 illustrates the device of FIG. 4 in bottom plan view; and

FIG. 6 is a fragmentary top plan view of the apparatus of FIG. I.

Referring now to the drawing in detail, and initially to FIG. I, there is seen one half of an upright, cylindrical tank in the process of being constructed in an exca- FIG. 6. Only one girder 6 is seen in FIG. 1. Its radially inner, longitudinally terminal portion rests on a collar 7 near the top end of the column 4. As is better seen in FIGS. 4 and 5, the collar 7 is split along a diameter, and the two identical parts of the collar have each a cylindrically arcuate sleeve portion 8 and a flat, radial flange portion 9 so that the parts of the collar 7 are L- 'shaped in axial section. Screws l0 circumferentially clamp the two halves of the collar 7 to each other in a" closed loop about the column 4 and tighten the loop so as to secure the collar in its 'vertical position.

- approximately hook-shaped or L-shaped bracket 11 which rests on the top of the wall 2 so that the upper I chord 12 of the girder 6 is entirely located within the tank cavity. The lower chord 13 of the' girder essentially consists of two, spacedly parallel steel beams which extend in upwardly concave arcs and are connected by cross bars 14a (see FIG. 3). The beams 13 are suspended from the upper chord 12 by vertical trusses 14, and are farthest from the chord 12 at about one third of the length of the girder 6 from the wall 2.

As is best seen in FIGS. 2 and 3, the upper chord 12 of the girder mainly consists of a box beam of hollow rectangular cross section in which a bar 15 is conformingly received with enough clearance to permit longitudinal movement. The bracket 11 is welded. to the free end of the bar 15 outside the box beam 12. This arrangement permits the girder 6 to be pre-fabricated and used in the construction of tank covers having uniform nominal diameter, but actually varying in diameter by a few inches as is unavoidable.

The rigidity in torsion q of the girder 6 is diagrammatically shown in FIG. I. Because of the asymmetrical fish belly of the girder, its radially outer portion is much stiffer than the central portion. Because the girders converge angularly in a common plane toward the column 4, the resistance of the ceiling form to the weight of the concrete to be poured therein is approximately uniform over its entire horizontal area. The form is bounded in all horizontal directions by an annular wall of sheeting 16 attached to the outer face of the tank wall 2 in a conventional manner, not shown, and projecting upwardly beyond the panels 5. Adhesively fastened pads 17 of rigid polyurethane foam cover the upper surfaces of the brackets 11 before concrete mix is poured into the form to a level 18 indicated by a chain-dottel line, the'pads 17 being horizontally apcrete mix has cured sufficiently to be fully selfsupporting, workmen can enter the tank and gradually release the screws on the collar 7. The girders 6 pivot on the brackets 11 against the resilient restraint of the foam plastic pads 17 as the collar 7 slides downward on the column 4. After the girders 6 are released from the flange portion 9, they may be withdrawn longitudinally from the recesses in theunderside of the tank cover provided by the yielding pads 17, and lifted from the tank cavity through the non-illustrated manhole. The two halves of the collar 7 are similarly retrieved for re-use, and the panels 5 may be either left in position or removed, and are suitably dimensioned for passage through the manhole if intended to be used again. The disassembly of the ceiling or cover form is simple, and its recovered elements may be used again in another tank of equal or similar configuration.

For structural strength, most upright tanks are of cylindrical shape. The invention, however, is not limited to such a tank shape. The collar 7 may be modified to match a column whose cross section is a square, elongated rectangle, or any other shape, and a tank whose top is not circular calls for girders 6 as carriers for the panels 5 which vary in length in an obvious manner. A

tank whose horizontal length is much greater than its horizontal width may require more than one column for supporting the ceiling or cover of the tank, and the invention is readily adapted to this tank configuration and many others in an obvious manner.

It should be understood, therefore, that the foregoing disclosure relates only to a preferred embodiment of What is claimed is:

1. An arrangement for pouring a concrete ceiling comprising:

a. an upright supporting column having an axis;

b. an upright wall extending about said column in radially spaced relationship, said wall circumferentially bounding a cavity aboutsaid column;

c. a collar having a plurality of parts;

d. fastening means releasably tightening said parts about the topmost portion of said column in a position in which said collar projects radially from said column;

e. a plurality of horizontally elongated carriers, each carrier having an inner longitudinally terminal portion supported on said collar and an outer longitudinally terminal portion supported on the top surface of said wall;

f. panel means supported on said carriers, said panel means substantially closing said cavity in an upward direction and constituting the bottom of a form;

g. annular sheeting means upwardly projecting from said wall beyond saidpanel means for horizontally containing concrete poured in'said form; and

h. recess-forming means superimposed on each of said outer terminal portions for forming a recess in said poured concrete.

2. An arrangement as set forth in claim 1, wherein each of said parts has two portionsjoined in an approximately L-shaped cross section, said fastening means fastening said parts to said column in such' a manner that one portion of each part is upright and contiguously adjacent said column, and the other portion of said part projects horizontally away from said column.

mately hook-shaped bracket members resting on said top surface.

5. An arrangement as set forth in claim 4, wherein said recessforming means include a resilient pad super imposed on each bracket member, said pad being horizontally substantially coextensive with said bracket member. 

1. An arrangement for pouring a concrete ceiling comprising: a. an upright supporting column having an axis; b. an upright wall extending about said column in radially spaced relationship, said wall circumferentially bounding a cavity about said column; c. a collar having a plurality of parts; d. fastening means releasably tightening said parts about the topmost portion of said column in a position in which said collar projects radially from said column; e. a plurality of horizontally elongated carriers, each carrier having an inner longitudinally terminal portion supported on said collar and an outer longitudinally terminal portion supported on the top surface of said wall; f. panel means supported on said carriers, said panel means substantially closing said cavity in an upward direction and constituting the bottom of a form; g. annular sheeting means upwardly projecting from said wall beyond said panel means for horizontally containing concrete poured in said form; and h. recess-forming means superimposed on each of said outer terminal portions for forming a recess in said poured concrete.
 2. An arrangement as set forth in claim 1, wherein each of said parts has two portions joined in an approximately L-shaped cross section, said fastening means fastening said parts to said column in such a manner that one portion of each part is upright and contiguously adjacent said column, and the other portion of said part projects horizontally away from said column.
 3. An arrangement as set forth in claim 2, wherein said fastening means include connecting means releasably connecting said upright portions in a closed loop about said column, and tightening said loop.
 4. An arrangement as set forth in claim 1, wHerein said outer terminal portions include respective approximately hook-shaped bracket members resting on said top surface.
 5. An arrangement as set forth in claim 4, wherein said recessforming means include a resilient pad superimposed on each bracket member, said pad being horizontally substantially coextensive with said bracket member. 